1. Field of the Invention
This invention relates to a disk drive suspension comprising a microactuator element of, for example, lead zirconate titanate (PZT).
2. Description of the Related Art
A hard disk drive (HDD) is used in an information processing apparatus, such as a personal computer. The HDD comprises a magnetic disk rotatable about a spindle, a carriage turnable about a pivot, etc. The carriage, which comprises an actuator arm, is configured to be turned transversely relative to tracks about the pivot by a positioning motor, such as a voice coil motor.
A suspension is mounted on the actuator arm. The suspension comprises a load beam, flexure superposed thereon, etc. A slider, which constitutes a magnetic head, is mounted on a gimbal portion formed near the distal end of the flexure. The slider is provided with elements (transducers) for accessing data, that is, for reading or writing data. The load beam, flexure, slider, etc., constitute a head gimbal assembly.
In order to overcome the increase in the recording density of disks, the magnetic head should be more precisely positioned relative to the recording surface of each disk. To attain this, dual-stage-actuator (DSA) suspensions have been developed that combine a positioning motor (voice coil motor) and microactuator element made of a piezoelectric material, such as lead zirconate titanate (PZT).
The distal end of the suspension can be quickly moved by an infinitesimal distance in a sway direction (or transversely relative to tracks) by applying a voltage to and thereby deforming the microactuator element. As disclosed in Jpn. Pat. Appln. KOKAI Publications Nos. 2007-234982 (Patent Document 1) and 2008-287835 (Patent Document 2), moreover, there are also known co-located DSA suspensions in which a slider and microactuator element are mounted on a gimbal portion of the suspension. In the suspensions described in Patent Documents 1 and 2, measures are taken to suppress migration between conducting members in a circuit part of a flexure.
In order to electrically connect an electrode of the microactuator element and a conductor of a conductive circuit portion, an electrically conductive paste, such as a silver paste, may be provided between the electrode and conductor. The silver paste comprises, for example, a thermosetting binder and silver particles mixed therein and can be cured by heating. In DSA suspensions that have recently been downsized more and more, especially in those ones with a microactuator element and slider mounted on a gimbal portion, it is also important to ensure electrical insulation between the conductor and silver paste on the gimbal portion with a small area.
Even if a certain distance for electrical insulation is maintained between the silver paste and conductor, silver ions in the silver paste may sometimes move along adhesive interfaces of, for example, an electrically insulating adhesive due to a potential difference. The movement of the silver ions causes electrochemical migration (ion migration), that is, growth of a causative agent for an electrical short, such as dendrite, along the adhesive interfaces. According to conventional migration preventive measures, migration between conducting members is suppressed. In the conventional case, however, no consideration is given to ion migration that occurs between a conductor and electrically conductive paste on a microactuator mounting section, and the growth of the causative agent for short-circuiting along the adhesive interfaces is out of account.